Lung cancer is mainly caused by carcinogens, and incidence of lung cancer has been on a rising trend worldwide. In South Korea, lung cancer having the highest mortality rate among all cancers is regarded as one of the most serious diseases. Lung cancer is divided into two groups, small cell lung cancer (SCLC) and non small cell lung cancer (NSCLC), and the NSCLC is also divided into sub-groups: adenocarcinoma, squamous carcinoma, large cell carcinoma, and adenosquamous carcinoma, depending on lung tissue types. Clinical manifestations, such as areas prone to occur depending on different lung tissue types, progression type and speed, and symptoms, may vary as well as treatment methods.
Most of lung cancers cannot be treated by chemotherapy and radiation therapy. Chemotherapy and radiation therapy may be used by reducing a size of SCLC while complete treatment cannot be expected from chemotherapy and radiation therapy. Since an anticancer drug is less effective in NSCLC than SCLC, the treatment of lung cancer using chemotherapy only is almost impossible. Instead, complete removal of tumors in a surgical manner is the only effective treatment. However, about 30% or less of patients with lung cancer have tumors that cannot be totally resected when being diagnosed. In addition, only one-third or less of the patients survive for 5 years after surgical resection is done.
Therefore, there is a great demand for a method of more accurately detecting the early diagnosis of lung cancer and the spread of cancer and more effectively treating lung cancer.